The present invention relates to an internal combustion engine.
There has been known a internal combustion engine which is provided with an cylinder inside fuel injection valve for injecting fuel into a combustion chamber, and an intake passage fuel injection valve for injecting the fuel into an intake passage, and controls fuel injection amounts at the respective fuel injection valves according to rotation speed, load, etc. of the internal combustion engine.
By feeding the fuel which is pressurized by a high pressure fuel pump to the cylinder inside fuel injection valve, it is possible to inject the fuel into the combustion chamber.
The high pressure fuel pump is fixed, for example, to a cylinder head of the internal combustion engine, and is operated with rotation of a cam shaft of the internal combustion engine.
Further, there is disclosed in Japanese Patent Publication No. 5730387, such a structure of a high pressure fuel pump, in which the fuel is pressurized as described above, that a part of the fuel which is fed from the fuel tank is allowed to pass through a housing of the high pressure fuel pump, without being pressurized to a high pressure, and can be fed to the intake passage fuel injection valve.
As the results, in Japanese Patent Publication No. 5730387, it is possible to cool the high pressure fuel pump with the fuel which is fed to the intake passage fuel injection valve, when the fuel is fed to the intake passage fuel injection valve only. Accordingly, when the internal combustion engine is operated by feeding the fuel to the intake passage fuel injection valve only, it is possible to restrain heat-up of the high pressure fuel pump due to the heat which is transmitted from the cylinder head of the internal combustion engine.
However, in the art disclosed in Japanese Patent Publication No. 5730387, the housing of the high pressure fuel pump must be provided with a fuel outlet and so on for feeding a low pressure fuel. Therefore, as compared with a high pressure fuel pump which is employed in such an internal combustion engine that the intake passage fuel injection valve is not provided and feeds the high pressure fuel only, it is necessary to impart a different structure to a body part of the housing or so, which will make common use of components difficult.